For the exponential function f, the value of f(1) is k, where k is a constant. Which of the
following equivalent forms of the function f shows the value of k as the coefficient or the
base?

f(x) = 50(1.6)^*+1
f(x) = 80(1.6)^*
f(x) = 128(1.6)^*-1
f(x) = 204.8(1.6)^*-2
x=*